Apparatus for graining



Dec. 23, N43. COREY ET AL APPARATUS FOR GRAINING Filed Aug. 5, 1940 4Sheets-Sheet l U s U Vn v. @0 0 a E L R UHAflWO N62 T 05 W mm P F 0 5M05 Hg 7 5 Dec. 21, 1943.

F. COREY ETAL APPARATUS FOR GRAINING Filed Aug. 3, 1940 4 Sheets-Sheet 3Dec. 21, 194-3. COREY ETAL 2,337,453

APPARATUS FOR GRAINING Filed Aug. 3, 1940 4 Sheets-$heet 4 A TTORNEYPatented Dec. 21, 1943 APPARATUS FOR GRAINING Flournoy Corey, FredDoetzel, Jr., and Robert Donald Pitts, Cedar Rapids, Iowa ApplicationAugust 3, 1940, Serial No. 350,636

14 Claims.

This invention relates to equipment and machines for preparing andgraining plates of metal, glass and the like and is particularlyconcerned with equipment and machines used in offset lithography.

Such so-called graining machines comprise,

in general, a stationary base on which a tray is mounted for gyratorymovement. Lithograph plates, which are generally thin sheets of zinc oraluminum are placed in the bottom of the tray and firmly clamped inplace. The plates'are then covered with balls of steel, glass,lignumvitae, or other material, which are caused to rotate or roll overthe entire surface of the plates due to the gyratory movement of thetray. In a preferred type of machine, the speed of the tray may beregulated. Grit, such as sand, quartz, or the like, of the proper gradeand having the desired abrasive qualities, is placed in the tray alongwith a sufficient quantity of water. The graining of the plates isaccomplished by the abrasive action of the grit on the plates due to theweight and the sliding or rolling effect of the marbles.

The majority of the devices of the prior art have made use of a pair ofeccentrics, one located near each end of the tray for imparting thegyratory motion to the tray. These have been simultaneously rotated, asa general rule, by means of a cross shaft and the necessary bevelgearing.

One of the greatest troubles encountered with 'a machine of this type ofconstruction is the wearing and consequent misalignment of the pair ofeccentrics. It is necessary that they be in perfect alignment and thatthey operate in .synchronism. Furthermore, in the devices ofthe priorart it has been necessary to make these eccentrics suificiently largeand strong to withstand the centrifugal forces exerted upon them by theconsiderable weight of the graining tray and the marbles while beingrotated at the speed wehave found to be most desirable for gran-ling,which is generally about 175 R. P. M. I I

Our invention advances a new concept of a graining machine in that asingle eccentric is employed and the graining tray is gyrated by thiseccentric by pure rotation and centrifugal force much as a bucket ofwater may be swung in a horizontal circle at the end of a rope. Thesingle eccentric has no part in supporting the tray or absorbing thecentrifugal force set up, but merely imparts a rotary movement to thetray.

are provided for supporting the tray, for determining the circle oftravel of the tray, and for absorbing and meeting the centrifugal forcesset up in the tray. F

It is, therefore, a primary object of our invention to provide animproved structure of this type utilizing'only a single eccentric, andone making use of cupped guiding and retaining members on both the baseand the tray in conjunction with ball-shaped members or cylindricalplates to both guide-the trayperfectly in its proper orbit, and also totake care of the centrifugal forces exerted by the weight of the tray.

It is another object ofour invention to provide such a structure as willbe simple and positive in operation and,further, to provide a simple andpositive means of aligning the required parts of the device. v r

It is a further object of our invention to provide a structure that willeliminate the necessity of counterweights' and the like;

It is a further object of the invention to provide a base for such astructure which may be taken apart, moved at a minimum of expense, andreassembled if necessary, while at the same time, to provide a base ofsuflicient weight to furnish the required solidity and freedom fromvibration necessary for the proper operation 'of a device of this kind.I

It is a still further object of our invention to provide a means forautomatically taking up-the wear in the supporting'and guiding means ina device constructed in accordance with my invention. r

Another and further object of our invention is the provision of meansespecially adaptable for clamping small lithograph plates in, the bottomof the tray of such a graining device.

Other and further features and objects. of the invention will be'moreapparent to thoseskilled 'in the art upon a consideration of theaccompanying drawings and following specification, wherein are disclosedexemplary embodiments of the invention, with the understanding, however,that such changes may beimade therein as fall Within the scope of theappended claims, without departing from the spirit of the invention:

In said drawings: Figure ,1 is a view in. perspective of a deviceconstructed in accordance with one embodiment of our invention, with thetray of same in position for use.

Figure 2 illustrates the same machine with the g'rainin'g tray liftedfor 1 the removal ofthe marbles. I Figure 3 illustrates, schematically,-the principle of supporting and guiding the tray on large balls in guidecups.

Figure 4 is a view in elevation, and partly in section, illustrating apair of guide cups constructed and used in accordance with oneembodiment of our invention.

Figure 5 illustrates a method of aligning such cups with each other andwith the drive shaft.

Figure 6 is aview in perspective to illustrate an automatic take-up orover-ride device for driving the tray from the single driving eccentricand as constructed in accordance with our invention.

Figure 7 is a View, partly in elevation and partly in section, ofsupporting, and guiding members constructed according to a modified formof our invention.

Figure 8 illustrates another modified form of supporting and guidingmeans.

Figure 9 illustrates a base for such a graining machine as constructedin accordance with one embodiment of our invention.

Figure 10 is an elevational View of one of the piers of the base shownin Figure 9, partly broken away and partly in. section to more clearlyillustrate the construction.

Figure 11 is a partial View in perspective showing, in particular, thesub-frame of a machine such as that illustrated in Figures 1 and 2 andshowing the relative positions of the cup members.

Figure 12 illustrates a clamping means as constructed in accordance withour invention, and

Figure 13 is a view in perspective of a graining tray and illustrates,in particular, the clamping means devised for holding plates in thebottom of the tray.

Referring now to the drawings, and to Figures l and 2 in particular;these figures indicate the general appearance and construction of agraining machine built in accordance with one embodiment of ourinvention. A base which may be of monolithic concrete construction, andindicated generally at It), has upstanding piers at the ends, as at andI2, to the top of which are bolted channel members l3 and I4. These formthe end bars or members of an H-shaped frame I 5. The cross bar 16 ofthe H frame serves to support a gear case i! enclosing a speed reductionmechanism which may be of the worm .or bevel gear type and driven by amotor l8 and belting H9. The power take-off of the speed reductionmechanism extends upwardly through the center of the H frame. A crank,not shown in Figures 1 or 2, is mounted on the power takeoff shaft, thecrank pin being swingably received in a ball or roller bearing linkmember,

the other end of which is pivotally connected to the sub-frame. 25 nearthe center of same. The outer corners of the sub-frame are supportedupon large balls, preferably of steel, in the case of the relativelylarge machine shown. These are rotatably received between cups, asindicated generally at 30 and described hereinafter in greater detail.

These cups and balls serve not only to support the tray in a levelposition and permit it to rotate, more or less in accordance with usualpractice, but also serve to fix the orbit of rotation 1 The sub-frame,indicated generally at 25, may be constructed of structural members,such as channel irons, with the longitudinally extending memberspositionedas shown at 26 to permit asst-s53 other longitudinal members28 and 28 attached to the bottom of a graining tray structure, indicatedgenerally at 15, to jackknife into the sub-frame. Other cross memberssuch as those shown at 29, located transversely of the bottom plate ofthe tray 15, are adapted to drop within the cross member 21 of thesub-frame and also to act as a hinge at the opposite end of the tray.

The tray itself is preferably constructed of heavy sheet metal with amarble receptacle 36 at one end to receive the marbles while the machineis being loaded or unloaded.

One of the most important features of our invention, in addition to themethod used, is the structure including the balls and cups, which isadapted to not only support the tray for rotation, but also to guide thetray in a perfect gyratory movement, and also to take up side thrust dueto centrifugal forces set up by the rotation of the heavy graining tray.

This principle embodied in our invention is indicated schematically inFigure 3, and in Figure 4 a pair of supporting cups and a ball are shownpartly in elevation and partly in section.

It is preferable, in a graining machine constructed in accordance withour invention, that each corner of the structure be provided with a pairof cups, as stated before, and as indicated generally at 30, and a ball3! positioned between the cups so as to roll around the inner surface ofthe lower cup and, at the same time, support the upper cup. Each of thelower cups, 32, is mounted by means such as the bolts 34 on the uppersurface of the H frame [5, previously described. Each of the upper cups33 is attached in a similar manner to the under surface of the sub-frame25. It is necessary that these upper and lower companion cups be inperfect vertical alignment, as will be hereinafter described inconnection with Figure 5.

The balls 3| may be of any convenient size, but I have found that a ballof approximately 2 inches in diameter is entirely suitable for use in amachine of this type and of ordinary size. It is obvious that the amountof throw to be imparted to the tray of a device constructed in thismanner may be governed by the diameters of the companion cups, that is,by reducing or increasing the distance between the center lines 34 and35 shown in connection with the lower cup 32.

It is preferable that the internal depth of each cup be slightly lessthan the radius of the ball supporting member 3| and as indicated at 33ain order to provide a slight amount of clearance between the upper andlower cup members. It is also preferable that the inner edge of eachcupped surface be slightly ch-amfered, as shown at 36. It is advisablethat the balls and cups operate with a continuous supply of lubricantand we have found that the chamfered edge of the cup member prevents thelubricant from being forced completely out of the cup.

If desired, guide members 37 may be provided in the exact center of eachcup member to prevent the Whipping back and forth of a graining trayduring the starting or stopping period. These guides may take the form,shown in Figure 4, of the rivet-like member 31 having a more or lesscone-shaped head 31a and adapted to be driven or threadedly received inan opening 38 at the exact center of each cup member. It will beapparent that the size of this central guide member may vary and willdepend .upon therelation between the size of the ball and the in ternaldiameter of the cup.

The cup-like guiding and supporting mea may takeother forms than thatshown. For instance the balls heretofore described may take the form offlat disk-like members 96 and the cups be provided with flat saucer-likedepressions 91 to receive the disks, as in Figure '7. Cranks, such asshown at $23 in Figure 8, may be substituted. These cranks may be in theform of fiat supporting discs having spaced crank-pins 99 and. it'llwith the crank-pins received for rotation in openings H32 in the platesH33 and Referring again to Figure 3, the crank or eccentric drivingmeans, illustrated generally at 49 is positioned in an approximatelycentral location relative to the supporting cups. This eccentricmechanism may of course comprise a simple crank member such as the oneindicated at 4!, with the crank pin Ma thereof received for rotation ina bearing member positioned on the lower surface of the sub-frame. Sucha structure, however, and with an exception which will be hereinafterdescribed in detail, though possible, is not entirely satisfactory sincethe throw of the crank or eccentric must coincide exactly with the throwof the tray which is of course otherwise determined by the balls and cupmembers.

It will be obvious that if the throw of the crank is less than the throwpermitted by the cups, the crank itself will bear most of the radialload set up by the centrifugal forces due to the rotation of the tray.Furthermore, if the throw of the crank is greater than the throwpermitted by the cup guide members, the balls will be forced to ridehigher up on the sides of the cups than they would do normally.

We have, therefore, provided the automatic adjustment and wearcompensation eccentric structure illustrated generally at to and shownin detail in Figure 6. This structure preferably includes the crankmember 3! having a crank pin lla upon which one end of a draglink 43 ispivotally received. The opposite end of the drag link is provided with abearing member 44 preferably of the ball or roller bearing type, andthis bearing is received on a stub shaft 46 extending downwardly fromthe lower surface of the sub-frame Z5 and preferably at the centerthereof. This stub-shaft may be in the form shown and include a shoulderll and a threaded portion 58, which may be mounted through a hole in thesub-frame and rigidly fixed in place by means of the nut ii}. It is ofcourse desirable that means be provided such as the grease fitting 55for permitting all bearing surfaces to be lubricated and that cap orcover means, not shown, be provided for covering or closing the bearingrace dd in order to exclude foreign material.

If the cup structures are constructed with guide pins such as 3?, thetray member will usually follow the path defined by the cup members withthe supporting balls following the inner surfaces of the cups.

In case such guide pins are not used, other means such as the stopmember 52 may be used. for forcing the compensating link 43 outwardly tothus cause the supporting balls to ride against theouter walls of thecups during the starting n stopping periods when centrifugal force alonewould be insufficient to prevent whipping.

The adjustable stop member'ez may be mount- In constructing a device inaccordance withour invention, it is desirable that the companion cups beplaced in perfect alignment and also that the stub shaft fit must be inperfect alignment with the drive shaft 42. I have therefore devised-themethod and-means for accomplishing this result,

as shown in Figure 5. f A centering pin 55 ismo-unted in the sub-framein place of the stub shaft 36, the lowerpointed end .of the centeringpin being adapted to be received in a center mark or cupped recess inthe center of the top end of the drive shaft 42. The cups are thenmounted on the frame and sub.- frame with the companion cups inperfectvertical alignment. Thismay b accomplished bymachining the outersurfaces of the cups concentric with-the inner surfaces and of suchadiameter as to be snugly received within aligning rings or sleevesfil.Sleeve are of course provided for each pair of companion cups, and afterplacing them in position, the cups may be fixed in position bytightening'all the clamping bolts 34. :The aligning rings and aligningpin may then be removed andreplaced by the supporting balls and the stubshaft. g

It is obvious that other means may be used for aligning theparts of sucha device, but we have found this method and means simple, accurate,

and otherwise satisfactory. r

The base or frame of a graining machine is subject to heavybendingstrains, as wellas to a heavy load, and must, therefore, be ofsubstantial construction. Such a base may be constructed in accordancewith any of the commonly accepted methods including building up withside, end and reinforcing members of case iron or the like, or bybolting or welding structural steel members together to forma unitarystructure. We have found,-however, that bases constructed in such amanner may be relatively expensive as well as lack the weight and masswe have found to be desirable. Y

The base member illustrated in Figures l and 2 is, as stated before,of'monolithic concrete construction, and we have found that such a basehas the weight, mass, and rigidity necessary to properly absorbthe-forces set up in a device of this nature.-

In order to make such a base-member more practical as regardsportability, and easeof construction, we have devised the improved formof base'illustrated in detail in Figures 9 and 10. The metal frameworkof the base may be filled with concrete or the like. If it is necessaryto move the machine, the metal parts of the base may be stripped fromthe concrete, the machine moved, set up, and again filled with concreteat a minimum of expense;

Such an improved base includesin general, a pair of shell-like metalforms held in spaced re lation and into which concreteor the like may bepoured to form a pair of piers.

The shell-like form for each end pier includes panels or plate-like endmembers 62 and 63. These members are preferably relatively wide at theirbottom ends and tapered inwardly toward the top, as shown, and providedwith inwardly extending fianges'along all edges and as shown at 64 andat65 in Figure 10.

These endmembers t2 and 63 are preferably spaced apart by a plurality oftie rod members 66, each rod having a pair of nuts Gland 68 at each endthereof. These nuts may be adjusted as required toproperly space theendmembers of each form. It is desirable that two of these rod membersbe placed near the bottomsurface of each pier to provide for detachablyconnecting a pair of angle members '69 and 19, which members serve totie the lower ends of the two piers together to form a unitary basestructure as will be hereinafter further described.

Angle members such as shown at 12 may be provided along the lowerlongitudinal edges of both piers to protect the edges of the concretelater poured into place.

The shell of the pier may then be completed by attaching sufiicientplanks, as illustrated at 13, to each side of each pier to complete theform, or if desired, metal plates may be permanently attached to the endmembers along the flanged edges 63 and 64 to provide an all metal form.The flanges E extending inwardly from the upper edges of the end membersare provided with openings for the reception of mounting bolts l4 bywhich the H-shaped main frame may be mounted on the top of the piers.

It is preferable, in a base constructed in this manner, that the shellsor forms of both piers be set up on a level surface and tied together bymeans of the angle members 69 and 10. Both piers may then be filled withconcrete or the like and the H-frame placed in position and pulled downtightly against the top surface of the concrete by means of theattachment bolts 14. When the concrete is cured, the side rails may beremoved and the entire structure removed to the location where it is tobe used. It maythere be reassembled and blocked up until level. Cementgrout may be forced under the piers to form a solid, level footing. 7 Itwill be obvious, that with such a form structure, the concrete portionof the base may be cast in place after the forms have been set up at thedesired location of the graining machine, and in such case, the concreteitself will take care of any unevenness in the floor surface. It is of.course necessary that the form be leveled up before the concrete ispoured.

Cross rails l l--ll may be mounted between the side rails 99 and '59 forsupporting an electric motor Ha or other suitable drive means. 7 It ispreferable that such drive means be of the variable speed type. V

A graining machine including a base constructed in the manner abovedescribed may be readily disassembled and moved to another location'whennecessary. Means are provided for properly spacing and aligning thepiers at both the upper and lower ends and serve to tie the variousparts of the device together to form a substantially unitary base ofsufiicient weight in itself to make it unnecessary to bolt it to thefloor as is necessary with most devices of this nature.

The graining tray i5 may be constructed in accordance with any of thenumber of different side members ll may be made in the shape of a Z tonot only provide additional reinforcement for the plate-like bottom ofthe tray, but to provide a flat upper surface Tia on which the platehook members 88, comprising part of the plate clamping bars, may beengaged.

One end of the tray is provided with an end panel-18 on'which is mounteda hook member as shown at 19 to provide for lifting that end of the trayby means of a hoist or the like.

The opposite end of the tray is provided with a marble receiver 80 intowhich the marbles may be permitted to roll when the tray is tilted andin order to permit lithograph plates to be placed in or removed from thetray. A gate 8| may be slidably received in slide members 82, attachedto the sides of the graining tray, in order to hold the balls in eitherthe tray proper or in the ball receiver,

Thebottom of the marble receiver may be provided with a number of drainholes to permit the grained plates to be washed and the used grainingsand and water to be carried away. It may also be provided with a screenmember 83 to keep the graining balls from passing through the drainholes. This screen may be of such a size as to permit balls which havebecome too small for use to pass out through the drain openings with thewash water. I

The clamping bars may include a pair of channel members 95 and 81 placedso as to face each other and attached together at the ends by means ofbolts or the like. Hook members, such as that shown at 88 in Figure 12,may be pivotally mounted between each pair of bars and at each endthereof in such a manner as to permit the hook portion to engage underthe outwardly extending upper edge Tia of the side walls of the tray.

Screw clamps 9%] include block members 89 which are adapted to beslidably received between the channel-shaped bar members and threadedrods 9! which may be screwed downwardly through the block 89.

I have found it desirable, in the graining of small lithograph plates,that means such as the T-shaped member 92 be provided for clamping theplates to the graining tray along the edges thereof. This T-shapedmember preferably has the laterally extending portions 93 and 94chamfered off to provide a relatively thin edge up which the grainingballs may be permitted to roll when the machine is in motion. Thisconstruction permits the plates to be grained very closely to the edgesand, furthermore, does not permit the balls to move in the same givenpath at each edges thereof 'as by riveting or welding. The

clamping bars, indicated generally ates, may be 1 slidably supported andto the under edge of which revolution of the tray. This substantiallyeliminates the series of streaks frequently noticeable along the edgesof a plate mounted in a graining tray by means such as a bar havingvertical sides against which the balls may slide or come to rest.

In the construction of graining machines in the smaller sizes we havefound it possible to eliminate the over-ride or automatic crankcompensating device 48 by utilizing semi-resilient supporting balls inplace of the steel balls heretofore referred to in connection with thesupporting and guiding cups. Such balls may be of very firm rubber orthe like and, if desired, the cups may be made of material other thanmetal. We have found lignum-vitae satisfactory for the purpose.

In this modified form of our invention the throw of the crank is made tocorrespond as closely as possible to the throw permitted the tray by theguiding cups. The resilience of the balls issufiicient to compensate forany slight differences between the throw of the crank and the throwpermitted by the cups and also serves to "compensate for any slightimperfection in the cups.

It will be obvious, of course, that such a device,

utilizing semi-resilient ball members, is feasible only in smaller sizesof machines, since in larger and heavier machines, the weight of thetray and graining marbles would be sufficient to distort any ballresilient enough to serve as a compensating means.

Other means than that shown may be used for driving a device of thisnature. For example,

the gear case I? may be dispensed with if departing from the spirit andscope of our invention as set forth in the appended claims.

We claim as our invention:

1. In a graining machine including a tray, driving means for impartingmovement to the tray in a substantially circular path, means forsupporting the tray for free movement, and means separate from thedriving means and substantially coincident with the supporting means forcarrying the radial centrifugal load.

2. In a device of the character described including a base member and amovable member, a plurality of pairs of supporting and guiding cups, amovable separating member between each pair of cups, eccentric means fordriving the movable member in a circular path limited by the cups andseparating members, and compensating means operatively connecting themovable member and the eccentric means whereby the movable member may beslung outwardly by centrifugal force to the full extent permitted by theguiding cups.

3. In a device of the character described including supporting andguiding cups and movable supporting member therebetween, eccentric drivemeans, and means actuable by centrifugal force for regulating the throwof the said eccentric drive means to coincide with the circle ofrotation of the device as determined by the guiding cups.

4. In a device of the character described, a plurality of pairs of cupmembers and ball members received therebetween, each of said cup membershaving an inside diameter greater than the diameter of the ball members,and having an inside depth somewhat less than one-half the diameter ofthe ball, and guide pins positioned in the vertical axis of at least onecup of a pair of cups, said guide pins extending inwardly from thebottom of the cup a sufficient distance to cause the ball to rollagainst the periphery of the cup.

5. In a device of the character described, a base including two pair ofshell-like end panels, means for spacing the panels apart to define theends of a pair of piers, means for closing the open spaces between theedges of the end panels to provide box-like forms for receivingconcrete, means for spacing and ali ning in parallel position the formmembers thus formed, said means comprising rigid rails detachablyconnected to the end panels near the bases thereof, mounting platemembers, means for joining said plates to form a rigid frame, and meansfor mounting said frame on the upper surfaces of the end panel members.

,6. In a device of the character described including a rotatable tray, apair of piers in parallel relation, flanged plate-like members receivedover the top surfaces of the piers, a rigid cross member connecting theplate-like members to form an H-shaped frame, means for reinforcing theH-shaped frame, eccentric drive means for the tray positioned centrallyof the cross member, and tray guiding and supporting means substantiallycoincident with one another positioned near the ends of the flangedplate-like members.

'I. In a graining machine, a graining tray having the longitudinal sidewalls thereof flanged outwardly at the upper edges thereof, clampingbars adapted to rest on the upper surface of the flanged side walls,clamps slidably engaged in the clamping bars, and hook members pivotallymounted in the ends of the clamping bars and adapted to be hooked underthe flanged portion of the side walls.

8. In a graining machine, a frame, a graining tray, single eccentricdrive means mounted on the frame and operatively connected with the trayfor imparting motion to the tray in a circular path, other means forsupporting and guiding the tray including a plurality of cup membersmounted on the frame, companion cup mem bers attached to the tray, andsemi-resilient ball members positioned between the cups on the frame andthe cups on the tray.

9. In a graining machine including a tray, driving means for impartingmotion to the tray in a substantially circular path, a plurality ofmeans spaced from the driving means for supporting the tray for freemovement, said means comprising opposed cup-like members, and guidemeans, circular in horizontal cross section and. of smaller diameterthan the cup-like members, disposed between the said cup-like membersand adapted to be rolled about between the inner peripheries of theopposed cups for taking the radial centrifugal thrust of the tray.

10. In a graining machine including a tray, the combination of eccentricdriving means for imparting motion to the tray in a substantiallycircular path, a plurality of means spaced from the driving means forsupporting the tray for free movement, said means comprising opposedcup-like members, and guide means, circular in horizontal cross-sectionand of smaller diameter than the cup-like members, disposed between thesaid cup-like members and adapted to be rolled about between the innerperipheries of the opposed cups for taking the radial centrifugal thrustof the tray, the said eccentric means including means operable bycentrifugal force for increasing the radius of throw of the eccentric tocorrespond with the circle of movement of the tray as determined by thecup and guide members.

11. In a graining machine including a tray, the combination of aplurality of spaced pairs of supporting and guiding cup members, aneccentric for imparting motion to the tray in a hori zontal plane and ina substantially circular path, and drag-link means operativelyconnecting the tray and the eccentric whereby the throw of the eccentricis free to adapt itself to the circle of movement of the tray asdetermined by the guiding cups.

12. In a graining machine including a tray, a single driving eccentricoperatively connected to the tray near the horizontal midpoint of themass of the tray to impart a gyratory motion to that portion of the trayto. whichit is connected, and

means operative by reason of, the centrifugal forces set upby theeccentric for causing-all other portions of the tray to describe acircular path, said means including fiat surf-aces, balls tojsupportthetray and annular guide members disfposecl about the flat surfaces. tocontrol and limit to a circular movement the .motion imparted to thetray by the centrifugal force acting thereon. 13. In a graining machineincluding ai'tray for holding plates, driving means for imparting asubstantially circular movement to one part of the tray to. thus providecentrifugal rotating forces in the tray, and rotatable guiding means,

, 14. In a graining machine including a tray for holding plates, asingle power driven eccentric having connecting means for operativelyconnecting it to the tray to furnish a circular movement of rotation tothat part of the tray to which the eccentric is operatively connectedand other eccentric means at spaced intervals about and operativelyengaged to the tray for limiting and defining the movement of the trayat the portions of the tray to which the other eccentric means areengaged in a circular path, whereby all the elements of the tray arecaused to move in a Oil'- cular path by reason of the centrifugal forceset up by the power driven eccentric.

FLOURNOY COREY.

FRED DOETZEL, JR.

ROBERT DONALD PITTS.

